This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Track-HD is a multi-centre, multi-national prospective observational biomarker study in pre-manifest disease persons and early Huntington's disease patients, funded by the High Q Foundation. The primary objective of Track-HD is to determine what combination of measures is the most sensitive for detecting change during the natural course of pre-manifest and early HD. These will be validated as potential outcome measures for use in future disease-modifying drug trials. Some of these measures are morphometric image analysis techniques on MR brain volumes. In order to get the best images for analysis in this study, we are initiating a sequence optimization process for 3T images, in which we test MR sequences before choosing the protocol for the study. We are also assembling an Advisory Group of interested parties and imaging experts to ensure that this is an open process which compiles as many viable options for the sequence as possible. Sequence optimization for the imaging component of the TRACK-HD study will be conducted at 3T on Philips and Siemens scanners. It is anticipated that a T1-weighted (T1W) volume will be acquired on which standard image analysis procedures will be used. As a more exploratory step, a T2 volume will also be acquired. Our goal is to develop a sequence that can be used for more than just establishing pathology through a clinical read;it will allow interested groups to explore image analysis techniques.